[NET] core: add RFC2863 operstate

this patch adds a dormant flag to network devices, RFC2863 operstate derived
from these flags and possibility for userspace interaction. It allows drivers
to signal that a device is unusable for user traffic without disabling
queueing (and therefore the possibility for protocol establishment traffic to
flow) and a userspace supplicant (WPA, 802.1X) to mark a device unusable
without changes to the driver.

It is the result of our long discussion. However I must admit that it
represents what Jamal and I agreed on with compromises towards Krzysztof, but
Thomas and Krzysztof still disagree with some parts. Anyway I think it should
be applied.

Signed-off-by: Stefan Rompf <stefan@loplof.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 3 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index ef56c035d44e..8763c99fcb84 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2174,12 +2174,20 @@ unsigned dev_get_flags(const struct net_device *dev)
 
         flags = (dev->flags & ~(IFF_PROMISC |
                                 IFF_ALLMULTI |
-                                IFF_RUNNING)) | 
+                                IFF_RUNNING |
+                                IFF_LOWER_UP |
+                                IFF_DORMANT)) |
                 (dev->gflags & (IFF_PROMISC |
                                 IFF_ALLMULTI));
 
-        if (netif_running(dev) && netif_carrier_ok(dev))
-                flags |= IFF_RUNNING;
+        if (netif_running(dev)) {
+                if (netif_oper_up(dev))
+                        flags |= IFF_RUNNING;
+                if (netif_carrier_ok(dev))
+                        flags |= IFF_LOWER_UP;
+                if (netif_dormant(dev))
+                        flags |= IFF_DORMANT;
+        }
 
         return flags;
 }